Light fighter

Official roll-out of the United States Air Force's first Northrop F-5E Tiger II.

A General Dynamics YF-16 and a Northrop YF-17 flying side-by-side as a part of the Lightweight Fighter program.

This article refers to a class of aircraft. Light infantry is sometimes referred to in this fashion in the U.S. See: 7th Infantry Division (United States).

A light fighter or lightweight fighter is a type of fighter aircraft with a diminutive airframe, deliberately designed to fill a performance niche based on a high thrust-to-weight ratio and high maneuverability. The development of this concept was based on results from real world experience studies. In the U.S. ideas were founded upon shortcomings endured during the Vietnam War,^[1] while in Sweden the requirement was a Mach 2 capable versatile platform with good short-field performance for a defensive, dispersed basing plan in the event of an invasion.^[2] Typically, light fighters have been dismissed by military planners as being too limited in capability, but several light fighter designs already have proven combat records. Some of the light fighters of today are now being developed as or have variants converted into unmanned combat aerial vehicles to be added as force multipliers and minimize human casualties.^[3]

History

WWII

Caudron C.714

Bell XP-77 lightweight fighter

The original light fighter class developed out of a concern over the gradually increasing size and cost of the frontline fighters in the 1920s, and the earliest such program was the French Air Force's 'Jockey lightweight fighter program' of 1926, for which several aircraft, including the Nieuport-Delage NiD 48 and Amiot 110 were trialed without much success. These were possible because of a new series of late 1920s aircraft engines that delivered a high power-to-weight ratio, albeit at a low power rating. In order to make use of these engines, the aircraft using them had to be as light as possible. However, this is not always easy; some components cannot be scaled down.

Despite the failure of the Jockey program, another attempt was made during the late 1930s to modernize France's fleet of aircraft. Several more light fighter designs of wooden construction that could be built quickly were produced. The most numerous, with about 90 eventually being built, was the Caudron C.714 which exemplified the fundamental flaws of the light fighter concept: underpowered, underarmed, and limited endurance. Delivery began in early 1940, but France fell before many were built.

Similar British programs such as the Miles M.20 remained as prototypes and were cancelled without entering production. The Hawker Fury was initially developed as the "Tempest Light Fighter" a lightweight version of the Hawker Tempest although in practice the resulting naval Sea Fury was a full sized fighter, and weight reductions were minor.

The United States Army Air Corps also contracted for several light fighter designs based on the Ranger V-770 engine, an air-cooled inverted V12 engine, smaller than most of the Axis-designed engines of the same format, that delivered up to 700 hp. Fears of an imminent massive German attack was forthcoming led to plans to build fighters designs based on the Ranger, which could be rapidly put into production. Performance of the engine proved uninspiring, and aircraft designed around it failed to meet expectations, including the Bell XP-77, and by the time examples were flying the need had disappeared.

Early jets

The first jet light fighter in service was the Luftwaffe's Heinkel He 162 of 1945.

U.K.'s Folland Gnat under evaluation by the Yugoslav Air Force; dwarfed by several North American F-86 Sabres in the background.

Light fighters again became popular in during the early era of jet engine development, for much the same reasons. Jet engines scale downward quite well, and a number of very small and lightweight engines had become available. Many attempts have been made to produce relatively high-performance designs using these inexpensive jets. The only realized attempt at producing a turbojet-powered "light fighter" during World War II was the 1945-introduced Heinkel He 162A Spatz (German for "sparrow"), the winner of the Third Reich's Volksjäger, or "people's fighter" design competition to produce an emergency fighter to defend the by-then crumbling Third Reich. The He 162A was powered by a single BMW 003 jet engine, as specified in the Volksjäger design competition's rules.^[4] Some 320 of the He 162A aircraft had been completed by V-E Day, with hundreds more incomplete airframes on production lines scattered around the defeated Third Reich's territory.

The Folland Gnat was a British private venture design for a light fighter.^[5] Although not adopted by the U.K. as a fighter (but as a trainer), it did serve successfully as a fighter for the Indian Air Force.

The Luftwaffe's G.91

The NATO Light Weight Strike Fighter competition of the early 1950s led to designs such as the French SNCASE Baroudeur, Breguet Br.1001 Taon^[6] and Dassault Étendard VI, the Italian Fiat G.91 and Aerfer Ariete (derived from the Aerfer Sagittario 2) and the U.S. Northrop N-156F. The competition also compared engines and selected the Bristol Siddeley Orpheus - which had been developed for the Gnat - as the winner.

In spite of losing the NATO competition, Northrop's design was offered to the USAF where is found little interest. However, the introduction of the Mutual Defense Assistance Act led to the N-156 being placed in competition with several other US designs, which it handily beat in terms of cost. Becoming the Northrop F-5 "Freedom Fighter", just under 1000 were sold worldwide, and another 1,400 of the updated Tiger II version. This makes the F-5 the most successful light fighter to date, by far.

New generation and future designs

Northrop F-20 Tigershark

HAL Tejas

KAI FA-50

CAC/PAC JF-17 Thunder

Several attempts have been made to introduce newer designs in the same general performance range as the F-5, but none have been as successful. One such aircraft is the Northrop F-20 Tigershark, an evolution of the Northrop F-5 series but it lost to the F-16 in a sales battle, and only 3 were built.

In 1987 BAe developed the Hawk 200 as an air combat variant of the Hawk trainer for air-to-air, air-to-ground and maritime strike roles, operated by three countries.^[7]

The YF-16 along with the YF-17 was originally conceived under the Lightweight Fighter program, but both grew into highly capable multirole fighter designs. Now known as the F-16 Fighting Falcon and F/A-18 Hornet. Their Soviet counterpart Mikoyan MiG-29 was originally part of the Perspektivnyy Lyogkiy Frontovoy Istrebitel (LPFI, or "Advanced Lightweight Tactical Fighter") program.^[8] In the 1980s SAAB began a lightweight fighter design as a replacement for the Saab 37 Viggen. The resulting prototype was the JAS 39 Gripen first came out in 1989.^[9] The French Dassault Mirage 2000 was designed as a lightweight fighter that also evolved into a multirole aircraft, with sales to a number of nations.^[10]

The HAL Tejas is a new light fighter whose composite structure allows the aircraft to be lighter than an all-metal design. The first examples entered service in India in 2015, with squadron use expected by 2017 or 2018. Several hundred aircraft are planned.^[11]

South Korea's T-50 Golden Eagle designed by Lockheed Martin with Korea Aerospace Industries is based on the F-16 multirole-fighter.^[12][13] Its latest variant called the FA-50 Fighting Eagle is designated as a light fighter while retaining its trainer capabilities using the same air frame as the T-50 advanced trainer introduced in August 2002.^[14] It is now deployed with South Korea's Air Force and the Philippine Air Force, replacing their aging Northrop F-5A/B and Northrop F-5E/F multirole light fighters and trainers.^[15][16]

In 2003, a lightweight fighter developed by Chengdu Aircraft Corporation of China and marketed by Pakistan Aeronautical Complex as the JF-17 Thunder.^[17] it was officially inducted into the Pakistan Air Force in February 2010.^[18] To date, 50 block 1 aircraft and 16 block 2 aircraft have been delivered to PAF. The Block 3 is expected to be introduced in 2018. A twin seater variant is in undergoing flight testing as of late 2015.

Unmanned fighter aircraft

By dispensing with the mass of the pilot and the cockpit equipment, and by eliminating the physical human g-force limitations, the concept of remotely controlled fighter aircraft may allow higher performance. The intention of unmanned lightweight fighters is to be a force multiplier rather than a full replacement of main fighters.^[19] The US Navy is currently studying using a drone to dogfight other planes. Some factors have to be resolved such as enemy jet detection, maneuvering to firing position and shooting it down automatically, which means still needing human help via another manned fighter jet helping the drone achieve its mission. Some ability to evade incoming missiles will be included into its capability.^[20]

References